[PATCH v3 1/9] dt-bindings: dma: nvidia,tegra186-gpc-dma: Add iommu-map property

[Akhil R <akhilrajeev@nvidia.com>]

Add iommu-map property to specify separate stream IDs for each DMA
channel. This enables each channel to be in its own IOMMU domain,
keeping memory isolated from other devices sharing the same DMA
controller.

Define the constraints such that if the channel and stream IDs are
contiguous, a single entry can map all the channels. If the channels
or stream IDs are non-contiguous, support multiple entries.

Signed-off-by: Akhil R <akhilrajeev@nvidia.com>
---
 .../devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
index 0dabe9bbb219..b5d8fd0b281d 100644
--- a/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
+++ b/Documentation/devicetree/bindings/dma/nvidia,tegra186-gpc-dma.yaml
@@ -14,6 +14,7 @@ description: |
 maintainers:
   - Jon Hunter <jonathanh@nvidia.com>
   - Rajesh Gumasta <rgumasta@nvidia.com>
+  - Akhil R <akhilrajeev@nvidia.com>
 
 allOf:
   - $ref: dma-controller.yaml#
@@ -51,6 +52,14 @@ properties:
   iommus:
     maxItems: 1
 
+  iommu-map:
+    description:
+      Maps DMA channel numbers to IOMMU stream IDs. A single entry can map all
+      channels when stream IDs are contiguous. In systems where the channels or
+      stream IDs are not contiguous, multiple entries may be needed.
+    minItems: 1
+    maxItems: 32
+
   dma-coherent: true
 
   dma-channel-mask:
-- 
2.50.1